<template>
    <div>
      <router-link tag="div"
                   to="/"
                   class="header-abs"
                   v-show="showAbs"
      >
        <div class="iconfont header-abs-icon">&#xe624;</div>
      </router-link>
      <div class="header-fixed"
           v-show="!showAbs"
           :style="opacityStyle">
        景点详情
        <router-link to="/">
          <div class="iconfont header-fixed-back">&#xe624;</div>
        </router-link>
      </div>
    </div>
</template>

<script>
export default {
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      let top = document.documentElement.scrollTop
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle.opacity = opacity
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  activated () {
    window.addEventListener('scroll', this.handleScroll)
  },
  deactivated () {
    window.removeEventListener('scroll', this.handleScroll)
  }
}
</script>

<style lang="stylus" scoped>
  @import "~styles/varibles.styl"
  .header-abs
    position absolute
    top .2rem
    left .2rem
    width .8rem
    line-height .8rem
    text-align center
    height .8rem
    border-radius .4rem
    background rgba(0,0,0,.8)
    .header-abs-icon
      color white
      font-size .4rem
  .header-fixed
    z-index:2
    position fixed
    top 0
    left 0
    width 100%
    height .86rem
    line-height .86rem
    text-align center
    color #ffffff
    background $bgColor
    font-size .32rem
    .header-fixed-back
      position absolute
      top  0
      left 0
      width .64rem
      font-size .4rem
      color: #fff
      a
        color: #fff
</style>
